The present invention relates generally to an improved electronic flasher for a camera having means for automatically cutting power input to the charging circuit thereof when the device is prepared to flash and, more particularly, to an improved electronic flasher of the type described which is capable of producing a flash sufficiently luminescent for picture taking for a finite period of time after power input thereto has been cut-off. The instant invention is suited to conventional cameras having built-in electronic flash units as well as cameras adapted to receive demountable flash units.
Conventionally, electronic flash units are activated or deactivated by a manual two-way switch having ON-OFF power input settings. There is a finite time lapse between the instant the device is activated and the instant the device is charged to a condition of flash readiness. Since the device is either incapable of producing a sufficiently luminescent flash or incapable of producing any flash until adequately charged, an indicating means, such as a glow lamp, is usually associated with the charging circuit thereof for the purpose of signaling when the device has reached a condition of flash readiness.
While illumination of the glow lamp is a positive indication that the device is charged for flashing, it is an unreliable indicator as employed in these conventional devices. For example, the glow lamp may continue to provide a positive indication after the ON-OFF switch is flipped to the OFF position although the device is only capable of producing a flash which is insufficiently luminescent for picture taking. This aspect of the operation of these devices represents a distinct disadvantage, and this condition is particularly likely to occur when the device has been unused and uncharged for a long period of time.
Retention of the minimum charge necessary for suitably flashing these conventional devices requires continuous charging of the unit unitl the instant of flashing. After flashing, the charging process is immediately recommenced unless the device is shut-off. Minimization or avoidance of this problem requires that the device be constantly charged, even during periods of non-use which shortens the useful life of the power source, usually batteries, employed in these devices.
Accordingly, the flasher devices constructed according to the instant invention include means for providing a suitably luminescent flash for a finite indicated period time after the power input thereto is cut-off.